| 摘要 |
The manufacture of pipes by deformation, such as pipe sections in an expansion joint, is generally done by forging of the heated pipe sections. In so doing the material structure is significantly modified, however, which can lead to weaknesses in the finished fabrication. In order to avoid this, the pipe 6, 5 can, according to the invention, be deformed in a press by means of a mandrel 8, 13 or die 11, which is provided with a conical taper 9, 14 and a conical narrowing 10 respectively, both with a cone angle 16, 17, 18 of between 15 and 20 degrees. This simplifies deformation whilst allowing it to be performed without heating the pipe, thereby avoiding structural changes in the material and hence any weakness therein. The mandrel 8, 13 drifts the pipe 6, 5, when it is pressed into the pipe, whilst the conical narrowing 10 of the die 11 presses the pipe 1 in and forms the conical end 2. This can happen because the material is rendered plastic owing to the heat generated by the deformation resistance. <IMAGE>
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